About Sakamoto... If there's one thing about his choices that would make me glad he might not work on more Metroid, it's his tendency to kill of everything! Retro had the decency to leave things open. They were actually expanding upon the Metroid universe and creating future potential. Sakamoto has this annoying tendency to annihilate everything he introduces into the series.
Metroid evolutions on SR-388? Nope, Samus blown 'em up.
Ridley? Kill him, blow up the planet he died on, create a bizarre clone of him, kill that off, have his corpse transform into a freaky alien mutated version, kill that off.
Space Pirates? Constantly kill them off in droves until there's no plausible chance of them returning.
X-Parasites? Metroid evolutions making a return? NOPE, blow up the space station AND the planet they reside on. At the same time.
The Prime series? Call it an "off shoot" of the series or something like that.
Frankly it's like Sakamoto's been trying to figuratively and LITERALLY kill the series for years. I don't care if he ever touches the series again if all he's capable of doing is eliminating potential instead of nurturing it.